Earlier quoted context omitted.
Who knows what positions each took behind closed doors, but do you think they aren't going into a negotiation all on the same page? Do you think they would allow someone in negotiations to take a position opposite to the company line? Also, relations does not mean advocate. He has relations with the customer, he is not obliged to advocate their views. Especially not when it goes against FBs interests.
"Developer relations" normally implies a role intended to encourage developers to use your platform. If they're just going to parrot the company line, then there's not much point in them existing, is there?
no, thats marketing.
Dev relations works with you once you are already using the platform. Don't get their intentions confused. They may be on your side with bug fixes and feature requests, but if you try to do something that goes against their company, why the hell would they be on your side?